The present invention relates to a compact keyboard system.
With the rapidly expanding developments of small computer systems, there has been an ever increasing demand for reducing the overall size of the computer system as well as the keyboard for entering data into the system. While the size of the computer system has been substantially reduced so that small computers can fit within a briefcase or a large jacket pocket, problems have arisen as far as the practicality of use of the keyboards on such computers. These various pocket size or small computers for briefcases have used a full set of keys on a keyboard but have substantially reduced the size of such keys. The small size of these keys has rendered it difficult to only actuate a single key for entering data when using the keyboard.
While a full keyboard with all keys and punctuation marks of a size sufficiently large for enabling information to actually be typed into the computer system is desirable for some types of operation, if the amount of information to be entered into the computer system is limited in nature then a full size keyboard for regular typing is unnecessary. The primary concern in this type of situation becomes the case and speed with which data can be entered into the computer system.
Various types of coded key formats have been developed for enabling codes representative of different alphanumeric characters to be entered into a computer system using a single key structure. Exemplary of such systems are those systems disclosed in U.S. Pat. No. 4,005,400 to Engdahl and U.S. Pat. No. 4,159,471 to Whitaker.
In the patent to Engdahl, a small data entry screen is provided on a portion of a watch surface. This data entry screen primarily consists of four pressure sensitive quadrants. By writing information across such quadrants in a particular order, it is possible to enter various numbers of 0 through 9. As indicated in the patent, by carefully writing the various numbers in a particular pattern each of the four quadrants will be activated in a particular different order thereby providing a coded signal corresponding to each of the different numbers of 0 through 9. In this manner, a numerical code can be entered through this data entry screen on the watch.
In the patent to Whitaker, special codes have been developed for each letter of the alphabet and for various punctuation marks. By writing these special codes on a data entry screen, which screen consists of four pressure sensitive quadrants, alphanumeric data can be entered into a computer system. In the operation of this system disclosed by the patent to Whitaker, one must remember the specific codes representing each character and punctuation mark or alternatively must continually refer to a chart showing the code for each of the alphanumeric characters and punctuation marks.
Other types of systems for enabling the entry of written data have been developed within the art. Exemplary of such other types of systems is the drawing board disclosed in U.S. Pat. No. 3,618,029 to Graven. The patent to Graven discloses an array of light-emitting light-sensing members which can be activated by a stylus for entering different codes representing different data to be entered into the computer system.
In addition, various types of optical displays utilizing a series of light-emitting bars or segments have been extensively developed within the art. These displays provide for the display of alphanumeric characters based upon which bars are activated for emitting light. Exemplary of these types of display systems are those disclosed in U.S. Pat. Nos. 3,495,232 to Wagner, 4,220,948 to Trame, and 4,224,615 to Penz. The patents to Wagner and Penz both disclose LCDs in which each character is formed by a series of lighted bars; these bar patterns have an outer box structure along with a plurality of bars extending within the box. These LCD display bars, however, only provide a display of information entered through another source within the system and are not utilized for enabling the entry of data. The patent to Trame discloses the formation of various characters using a 7-segment set of shutters; again this system is merely a display system and not utilized for the entry of data into a computer system.